Cells have their own recycling system: discarded cellular components, from individual proteins through to whole cellular organs, are degraded and the building blocks re-used in a different place. The scientific term for this recycling process is autophagy. In severely damaged cells, autophagy can also be a form of programmed cell death.
In this case, the cell uses the mechanism for complete self-decomposition. It is assumed that highly aggressive cancer cells use autophagy to resist tumor therapy. Investigations are leading to whether blocking the recycling system (autophagy) might be useful to support anti-cancer therapies. They are bascially rediscovering something reported 20 years ago (JNCI, 83:37-42, 1991).
This study had lead to the focus on the human tumor primary culture microspheroid (microclusters) platform. The functional profiling platform (phenotype analysis) studies cancer response to drugs from actual human microspheroids (tumor microenvironment), enabling it to provide clinically relevant predictions to individual cancer patients.
http://cancerfocus.org/forum/showthread.php?t=3651